A 42-year-old female presents with a 14-month history of intense fear that she has pancreatic cancer. She reports reading an article about a celebrity who died of the disease and has been preoccupied with the possibility ever since. She checks her abdomen for masses several times daily, has visited four different gastroenterologists, and has undergone two CT scans, an MRI, and an endoscopic ultrasound — all normal. Notably, she does not report significant abdominal pain, nausea, or other somatic complaints. Her distress is centered entirely on the meaning of minor bodily sensations such as occasional gurgling. She acknowledges her stomach feels 'basically fine' but remains convinced something is being missed. Which is the most accurate diagnosis?